Polar relay



A. H. ADAMS POLAR RELAY Nov. 25, 1947.

Filed Dec. 5, 1942 2 Sheets-Sheet 1 ARDEN H. ADAMS BY ATTORNEY Nov. 25, 1947. A. H. ADAMS 2,431,444

POLAR-RELAY Filed Dec. 5, v 1942 2 Sheets-Sheet 2 ARBEN DAMS BY v4- 4 A 77 ORNE Y ENTOR.

. Patented Nov. 25, 1947 PATENT 1 OFFICE POLAR RELAY Arben B. Adams, North Hollywood, Calif., assignor, by mesne assignments, to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application December 5, 1942, Serial No. 468,003

6 Claims.

. This invention relates to electrical relays, and more particularly to a polar relay of the dynamically balanced type. 1

Polar relays are useful wherever there must be a selective relay action dependent upon the direction of fiow of a direct current of electricity. Such relays are most commonly used in bridge circuits for energizing apparatus dependent upon the direction of unbalance of the bridge. used in bridge circuits, the relay must be responsive to minute current flow.

Polar relays have many applications in airplanes, but in the past there have been few relays which gave satisfactory performance in airplane usage. The intense vibration found on airplanes requires that an armature be dynamically balanced so that there will be no accidental and unintended operation. Further, since airplanes are constantly maneuvering and changing their line of flight, even the dynamically balanced type relay would be actuated when the airplane turned relative to the axis on which the relay was mounted. Jewel bearings have shattered under the constant vibration, and although such types of mounting were satisfactory for laboratory instru- 25 ments they were completely unsatisfactory for airplane usage.

The present invention meets many of the requirements for airplane usage, and is specifically designed for airplane or other severe usage. The present invention is a relay of the wound armature type, acting in a field which is preferably a permanent magnet field. Instead of using the normal single armature, two opposed coaxial armatures are used with the contact points mounted on the 'armatures instead of partly on a fixed body or frame, as in the past. The armatures are dynamically balanced, and further, there will be no movement of the armatures with respect to the contacts if the airplane should rotate on an axis parallel to the axis of the armatures. In addition, rugged ball bearings are used as mounts for the armatures instead of the fragile jewel bearings previously used. The armatures I are wound on an extremely light frame of plastic or a similar material, and thin strips of steel are inserted in the windings to align the armatures with the fields in which they act. Extreme sensitivity is obtained by winding the two armatures in series, one opposed to the other, multiplying When.

2 the sensitivity as compared to a single armature, for any given current flow.

It is therefore an object of the invention to provide a polar relay which is satisfactory for 5 use on airplanes. a

A second object is to provide a polar relay which has opposed armatures.

Another object is to provide a polar relay having a plurality of armatures on which the contacts are mounted, rather than having them mounted partly on a fixed frame.

Another object is to provide a polar relay having extremely light armatures wound on a plastic frame. 4

Another object is to provide a non-magnetic frame for an armature winding in which is inserted a strip of magnetic material to center the armature with relation to the field in which it acts.

Another object of the invention is to provide a polar relay having extremely rugged pivotal point bearings of the ball bearing type.

Other objects and advantages of the invention will be apparent in the following description and claims.

In the drawings forming a part of this fication:

Figure l is an isometric view of the polar relay embodying the invention, the'upper part of the relay housing being removed to show the position of the armatures;

Figure 2 is an isometric view of a spring plate bearing retaining member forming a part of the ball bearing mounts for the. armatures;

Figure 3 is a schematic drawing of an electrical bridge circuit in which the relay may be used for the control of a fluid system;

Figure 4 is an elevation view, in full section, along the line 4-4 of Figure 1; and

Figure 5 is an elevation view, in full section, of the invention taken along the line 55 of Figure 4.

Shown in Figure 3 is a circuit in which the polar relay may be used. A battery 200 supplies current 4 to parallel wires 20! and 200 having resistances 204 and 206, respectively. Contacting resistance 204 is a take-on 2l0 actuated by a manual lever 2 l2. Connected to take-off H0 is a wire 2 leading to a polar relay 8, the other side of which is 50 connected to a wire 216 leading to a take-oft 2|! specifield pieces I2 and I4 contacting resistance 288. Regardless of the rel-, ative sizes of resistances 284 and 208, there is an equal electrical potential for proportionate points along each. 11 at any time take-offs 2H] and 2I8 do not occupy corresponding positions on their relative bridges, a difference of potential will exist causing a. current to fiow through relay 8. The amount of current depends upon the amount of unbalance, and the direction of current depends upon the direction of unbalance.

Polar relay 8 has, for diagrammatic purposes only, an armature 220 adapted to connect with either a coil 222 or 224, depending upon the direction of current fiow through the polar relay. These coils are energized by a battery 228, one terminal of which is grounded. Coils 222 and 224. in turn, attract an armature 228 to contact.

either a wire 230 connectedto a solenoid 282 or a wire 234 connected to a solenoid 235. A battery 238 supplies current to armature 228.

Solenoids 236 and 232 operate a four-way fluid valve 240 having a pressure connection 242 and an exhaust connection 244. Conduits 248 and 248 are connected to the valve and lead to a doubleacting actuating cylinder 258, the movable member of which is mechanically connected to takeoil 2I8.

In operating the system of Figure 3, the pilot or other member of an airplane crew, moves manual lever M2 to the desired position. This creates a potential difference between wipers 2II| and 2I8,

causing a current to flow in the polar relay. This I current operates the relay and the second armature 228 in a direction to operate the proper solenoid 236 or 232 to move the actuating cylinder 250 in a direction corresponding to the direction of movement of wiper 2| II. When wiper 2I8 reaches the position corresponding to the wiper ZIII, current fiow ceases and the relays return to normal, shutting off fiuid flow. It will be appreciated that neither expansion nor contraction of fluid flow can upset the system, since it is inherently self compensating for fluid volume changes.

Referring to Figure 1, the polar relay 8 includes a cylindrical housing I 0 of magnetic material such as steel, having secured therein pole pieces I2 and I4, which are oppositely magnetized. This magnetization may be obtained by placing the cylindrical housing III and. the attached field pieces I2 and I4 between the tips of. a horseshoe magnet which is energized in any suitable manner to transfer its magnetism to the housing and the field pieces. Secured to the bottom of and spaced between them, is a plastic member I8 which supports two iron core members I8 and 20 placed in the same plane as the field pieces I2 and I4. Supported by core I8 is a frame 22 of plastic material upon which is wound armature wire 24. Frame 22 is free to rotate relative to core I8, the mounting of which will be later explained. Surrounding core 20 is a similar plastic frame 26 upon which is wound armature wire 28 connected in series with the wire 24 of frame 22. Mounted on the inner end of frame 25 are two contacts, 30 and 32, having suitable wires leading thereto from an overhead point. Mounted on the inner end of frame 22 is a contact 34 spaced between contacts 80 and 82.

When a current has passed through wires 28 and 24, -the two frames 28 and 22 rotate in opposite directions in the field, and contact 34 will strike either contact 30 or contact 32, de-

pending upon the direction of current fio The arrangement of parts is more clearly shown in Figure 4. There it will be noted that field pieces I2 and I4 are secured to housing I! by steel screws I3. Plastic member I6 is secured to field pieces I4 and I2 by brass screws I1, and iron core I8 is secured to plastic member I 3 by brass screws IS. The brass screws are used in place of steel ones so that there will be no deflection of or interference with the magnetic flux between field pieces I2 and I4. It will be noted that the air gap between iron core I3 and the field pieces I2 and I4 is very narrow, and just suflicient to permit the insertion of the frame 22 and its windings 24. In this connection it should be noted that frame 22 has channels formed in its ends, as indicated in Figures 1 and 5, but the side portions (shownin Figure 4) are completely out through, so that the air gap will be completely filled with windings and will not be unnecessarily wide due to the presence of .parts of an armature frame.

Also shown in Figure 4 are thev mountings for the various electric conductors. An inverted U- shaped frame 38 is secured in any suitable manner to field pieces I2 and I4. Placed on the top of frame 38 is a piece of insulating material 38, having a plurality of connector members 48 secured thereto by rivets 4|, the other end of the rivets being connected to extremely thin copper foil 42 which is preferably twisted so that its spring action will not be transmitted to the part to which it is connected. Each connector 48 is soldered to its respective conductor 44 placed above insulator strip 38.

It will be noted also in Figure 4 that placed vertically in field winding 24 are extremely thin pieces of steel 54, which are as high as the opening in frame 22 into which the wires 24 are wound. These steel strips 80, by magnetic attraction, normally center the frame 22 in the plane of the magnetic field. They are very thin, however, so that their magnetic attraction will not be great enough to interfere with the reaction of the current in wires 24 against the magnetic field.

The mountings of frame 22 and 28 are most clearly shown in Figure 5. There it will be noted that iron core I8 has a recess 52 in which is retained a ball bearing unit 84. A hole is drilled in frame 22 opposite ball bearing 84 and a steel point 58 is inserted therein, and bears against ball bearing 54. The outer side of core I8 is relieved centrally at 58. Spaced across this recess is a piece of spring bronze having a cup 82 formed therein retaining a ball bearing unit 84. A hole is drilled opposite ball bearing 84 in frame 22, and a steel point 66 is inserted therein, to bear against the ball bearing 54.

In assembly, the ball bearing unit 54 is first placed in core I8, and the frame 22 with point 56 is placed over core I8 with point 56 contacting ball bearing 54. While tilting the left end of frame 22 upwardly, point 66 is inserted and spring plate 60 is held against it. The outer ends of plate 60 are then deflected towards the left, forcing the cup portion 82 towards the right. This permits the spring member 60 to be slipped down over the edges of core I8 with the left end of frame 22 following, and when the final position is reached the spring member 60 is allowed to return to its normal position. When in its normal position, spring member 83 is just slightly depressed, maintaining a steady pressure against point so that there will be no looseness or play in the entire mounting system.

'I'he mountings of the wires are also shown in Figure 5. At the right a copper foil 38 leads is placed therein and its through a grommet on the upper surface offrame 26, and is connected to wire 28. The other end of wire 28 is connected to a copper foil I2 passing through a grommet 14 in the lowerpart of frame 25, which in turn is connected to a copper bar 16 passing through the length of plastic member l8. Connected to the other end of bar 16 is a thin copper foil 18 passing through a grommet 80 in the lower face of frame 22 and conductor. Thin copper foils 42 lead to the respective contact points 32 and 84. v

The current may also be fed to and from the coils through the ball bearings. This construction would eliminate entirely the spring action of the conductor. I

If it is desired, the entire unit may be immersed in oil to further dampen any vibration transmitted to the armatures 22 and 24. For this purpose, a synthetic rubber mounting 86 may surround housing l0, and a cup shaped cover 88 is placed over the entire unit. A dish shaped cover plate 90 may then be-screwed to cover plate 88 after the entire unit has been filled with oil. In such event, however, a liquid proof connection must be made for the conductors 44 to enter the housing, and this is also illustrated in Fi ure 5. A synthetic rubber bushing 92 is inserted in a hole in covering 88, and a rivet 84 ends peened outwardly so that it will grip upon the covering 88. The insulation from wires 44 is then removed and bare wire inserted in hollow rivet 94 and soldered therein to form a liquid proof joint.

The operation of the polar relay is as follows. The foils 68 and 82 are connected'respectively to 6 tween the contacts; a field structure having a pair of spaced-apart pole faces between which said armature members are positioned; independent actating windings for said armature members. said windings being interconnected in opposition whereby energizing current moves them in opposite directions to produce operative movement between said contacts; said armature members being physically substantially identical and mounted for oscillation about a common axis whereby movements of said members, due to their inertia, in response to bodil movements of the relay by external forces, are substantially identica1..

2. A polarized relay as described in claim 1 in which said armature members are dynamically balanced with respect to said axis.

3. A polarized relay comprising: a field structure comprising a tubular member of magnetized material having a pair of inwardly projecting opposite pole pieces having parallel pole faces elongated axially; an armature member having a winding disposed in a coil positioned between said pole faces; means supporting said armature member for oscillation about an axis intermediate and parallel to said pole faces, and contact means including a contact mounted on said armature 'for actuation in response to movement of said armature about its axis.

4. A polarized relay comprising: a field structure having a pair of elongated parallel juxtaposed pole faces; a pair of independently 'movable coaxial armature elements positioned subends of wires through which the control current passes. When current is passed through these wires, and consequently through each of the armatures, the armatures react in opposite directions in the field pieces l2 and I4 since they are oppositely wound; When this occurs, contact 34 (Figure 1) strikes either contact 30 or 82, depending upon the direction of current flow, and an electrical contact is made for completing a circuit which may operate any desired device. When the current is removed, the thin steel shims 50 (Figure 4) in the windings of the armatures causes the armatures to be centered with respect to the plane of the field, and both armatures return to the normal position shown, wherein none of the contacts are touching. Current in the opposite direction will cause contact 34 to touch the other contact, establishing a current in another set of control wires.

Although this invention has been described with reference to particular embodiments thereof, it is not limited to these embodiments, nor otherwise except by the terms of the following claims.

stantially end to end for oscillation about a common axis intermediate and parallel to said pole faces, said armature elements having windings interconnected in opposition; and cooperating contacts on said two armature elements adapted to be moved into and out of contact with each other in response to opposite movements of said elements.

5. A polarized relay comprising: a. field structure having a pair of juxtaposed pole faces of opposite polarity providing a magnetic flux therebetween; an armature structure carrying an actuating coil having a neutral position in the plane of said flux when there is no current in said coil; means pivotally supporting said armature structure for oscillation about an axis parallel to and between said pole faces; and a small element of paramagnetic material in said armature structure symmetrically disposed with respect to the path of said flux when said coil is in said neutral position, for providing a restoring force to return and retain the armature structure and said coilin neutral position when said coil is not energized.

' 6. In a polarized relay of the moving coil type having a field structure terminating in a pair of juxtaposed parallel pole faces of oppositepolarity providing a constant magnetic flux path therebe tween, a core of paramagnetic material interposed between said pole faces in spaced relation to both and defining a pair of air gaps in said flux path, and an armature structure comprising a hollow frame pivotally mounted for oscillation about an comer portions whereby said opposite sections of said winding can occupy substantially all of said air gaps between said pole faces and said core.

ARBEN I-l. ADAMS. 4

(References on following page) Name Dste Fleld -1 Oct. 3, 1905 Allen Mar. 6, 1908 Guenee Nov, 12, 1909 Young Feb. 7, 1905 Hartlg June 2, 1942 FOREIGN PATENTS Country Date Switzerland 1 Apr. 1, 192

France Jan. 31, 1921 

